Finding the Fourth Proportional to 15,501.84, 21,393 and 8,428.72

Step by Step Solution

1. Step 1: Write the proportion equation
   15,501.84 : 21,393 = 8,428.72 : x
2. Step 2: Convert to fraction form
   15,501.84/21,393 = 8,428.72/x
3. Step 3: Cross multiply
   15,501.84x = 21,393 × 8,428.72
4. Step 4: Simplify right side
   15,501.84x = 180,315,606.96
5. Step 5: Solve for x
   x = 180,315,606.96/15,501.84
6. Step 6: Final answer
   x = 11,631.88